Worth highlighting the QOI Image format (qoiformat.org) showing that you can also get significant image compression benefits with a simple 1-page specification [1]:
> QOI is fast. It losslessly compresses images to a similar size of PNG, while offering 20x-50x faster encoding and 3x-4x faster decoding.
> QOI is simple. The reference en-/decoder fits in about 300 lines of C. The file format specification is a single page PDF.
I recently built a small image optimizer for macOS since ImageOptim is mostly abandonware now. Specifically for folks who dislike complex build tools for this job https://shiboru.com
Most comprehensive write up of JPEG et al. I have ever come across.
I think the MozJPEG compression optimisations deserves a mention, as does where we started, with RLE encoding for printer things.
Also important for my personal understanding of JPEG is the context: slow CPUs and analogue screens. OG JPEG was optimised for this, MozJPEG changed the look up tables and the ubiquitous 'turbo' JPEG library to use a few more CPU cycles and save a few more bytes, whilst fixing the banding that was actually okay in the analogue days of old CRT monitors.
> QOI is fast. It losslessly compresses images to a similar size of PNG, while offering 20x-50x faster encoding and 3x-4x faster decoding.
> QOI is simple. The reference en-/decoder fits in about 300 lines of C. The file format specification is a single page PDF.
[1] https://qoiformat.org/qoi-specification.pdf
It's amazing to me how we much we can fill in the blanks to make something recognizable with such little data.
I think the MozJPEG compression optimisations deserves a mention, as does where we started, with RLE encoding for printer things.
Also important for my personal understanding of JPEG is the context: slow CPUs and analogue screens. OG JPEG was optimised for this, MozJPEG changed the look up tables and the ubiquitous 'turbo' JPEG library to use a few more CPU cycles and save a few more bytes, whilst fixing the banding that was actually okay in the analogue days of old CRT monitors.
Bookmarked the article for re-reading.